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Biology Midterm Review
Midterm review for chapters 1, 2, 3, 4, 5, 37, and 39
95
Biology
9th Grade
01/23/2011

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Cards

Term
Metabolism
Definition
all chemical reactions occuring within an organism
Term
Homeostasis
Definition
the ability of an organism to maintain a stable (constant) internal environment
Term
Reproduction
Definition
the process by which living things produce new organisms of their own kind
Term
Respiration
Definition
the process of releasing chemical energy that is stored in nutrients (occurs through a complex series of chemicals)
Term
Synthesis
Definition

chemically combining simple substances into more complex substances

Example: photosynthesis (see card #6 for complete definition)

Term
Photosynthesis
Definition
Making sugar from carbon dioxide, water, and the sun's energy
Term
Organelles
Definition

specialized structures within cells that carry out a specific function

Example: nucleus, ribosomes, mitochondria, etc.

Term
Prokaryotic Cell
Definition

cell without nucleus and cell organelles

Example: bacteria

Term
Eukaryotic Cell
Definition

cell with nucleus and cell organelles

Example: animal & plant cells

Term
Nucleus
Definition
the control center of the cell. Contains the genetic information (DNA) which is in the form of chromosomes. Typical humans have 46 chromosomes in the nucleus of every cell in our body except sex cells (eggs and sperm). Human sex cells each contain 23 chromosomes in their nucleus, which is 1/2 the normal genetic material
Term
Mitochondria
Definition
called the "powerhouse" of the cell because this is where cellular respiration occurs. During respiration, energy is extracted from food and is amde available for use by the body. Every single cell in our body has 10's-100's of mitochondria. All plants and animals utilize cellular respiration
Term
Ribosomes
Definition
the place where proteins are assembled. Most ribosomes are found attached to the endoplasmic reticulum (ER), but some are also floating freely in the cytoplasm
Term
Chloroplasts
Definition
where photosynthesis takes place. Chloroplasts are green due to the presence of chlorophyll (a green pigment). Chlorophyll is able to capture the energy from sunlight and store the energy as chemical bonds in sugar.
Term
Vacuoles
Definition
storage compartments found inside plant and animal cells. Vacuoles store food, water, and/or waste products. Plant cells have very large vacuoles which are necessary for storing extra water
Term
Cell Membrane
Definition

seperates the cell form its surrounding environment. This semi-permeable membrane controls what comes into the cell, as well as what leaves the cell. This helps the cell maintain homeostasis

  • has a phospholipid bilayer (see card #16 for complete definition)
  • Has  proteins that run through it. Some of the proteins act as channels, or bridges to help move substances accross the membrane; others act as chemical receptors for recieving messages from other cells
Term
Phospholipid Bilayer
Definition
the cell membrane is made up of two layers of lipids that act as a barrier
Term
Four differences between plant and animal cells
Definition

PLANT CELLS                ANIMAL CELLS

 

1. Have a rigid cell wall/Have a fluid cell membrane

2. Contain chloroplast (for photosynthesis)/Do not contain chloroplasts

3. Have a large, central vacuole for storing water/Have only small, scattered vacuoles

4. Do not contain centrioles/Contain centrioles

            

Term
Diffusion
Definition

movement of molecules from ana area where there are few molecules to an area where there are few molecules. This happenes all by itself due to random movement of the molecules (like letting a ball roll down a hill)

Example: spray perfume in a room and it is very strong in the spot where you sprayed it. Wait 10 minutes and the whole room will smell like perfume due to diffusion of perfume molecules

Term
Active Transport
Definition
movement of molecules from an area where there are few molecules to an area where there are many molecules. This is going against normal diffusion; therefore it requires and input of energy (like rolling a ball up a hill). This is also importaint when a cell needs more of a specific type of molecule inside the cell than it does outside the cell. It pumps in extra molecules so there are lost of molecules stored inside.
Term
The Scientific Method
Definition
the creation of valid scientific experiments that can be repeated by other scientists in the future
Term
Hypothesis
Definition
a reasonable guess, or possible explanation for an observed set of facts
Term
The Scientific Method: Step 1 - Make Observations/Define the Problem
Definition
The process starts when a person sees or reads something that interests them. Scientists then form a question concerning what they have seen or read, which is usually followed by a search for information on the topic - to see what is known and what experiments have already been done
Term
The Scientific Method: Step 2 - Formulate a Hypothesis (see card #21 for definition)
Definition

The scientist then asks a reasonable question about their subject.

Example: A plant that is watered with sugar water will grow taller than a plant that is watered with plain water.

Term
The Scientific Method: Step 3 - Test the Hypothesis - Create an Experiment
Definition
In order to support or reject the hypothesis, the scientist must create an experiment to test it. The design of the experiment is critical. A well constructed experiment can explain a great deal about a question, whereas a poorly constructed experiment will tell you little or nothing. The scientists also use a controlled experiment (see card #25 for definition)
Term
Controlled Experiment
Definition

where two identical experiments are set up at the same time. The scientist then decides to change one thing (s)he will change (a variable), like the amount of water, adding a substance to the water, etc.

(see cards #26 and 27 for control groups and experimental groups)

Term
Control Group
Definition

an experiment conducted without the variable. The control tells us what we would expect under normal conditions, and allows us to see the actual effect of changing one variable

Example: To test the hypothesis that a plant that is watered with sugar water will grow taller than a plant that is watered with plain water, we set up to identical experiments.

Experiment 1: we have 10 bean plants growing in a room. We water these plants with plain water once a day for two weeks. Every day we measure the height of each plant. This is the CONTROL group.

(see Experiment 2 on card #27)

Term
Experimental Group
Definition

the same experiment is conducted as for the control group, only one variable has been added though

Experiment 2: this is set up exactly like the control group - 10 bean plants, growing for two weeks in the same room, same amount of water, same amount of light... but for this group, we add 10 grams of sugar to the water every day. This is the EXPERIMENTAL group, and sugar is the independent variable

Term
The Scientific Method: Step 4 - Observe and Measure
Definition
Science requires the gathering of large amounts of data in order to be able to explain the results to the public. Every experiment must therefore have some quantifiable data that can be collected (height, weight, specific health measurements like temperature, etc.)
Term
The Scientific Method: Step 5 - Analyze Data
Definition
Once data has been collected, analysis of the data must occur (what does the data mean?). This often involves the use of statistics, and data are almost always presented in the form of a graph or chart to make it easier to read
Term
The Scientific Method: Step 6 - Conclusion/Report Observations/Publish Data
Definition
When doing research in science, it is always important to let other people know about what you have found so that progress can be made in out understanding of life. Scientists publish their data in special research journals that are available to the public in university libraries
Term
Why scientists use large sample sizes
Definition
The more data collected, the more accurate the data will be. If a test of a drug is carried out on two people, we can't really say for sure how this drug is going to work on most people. If instead, we test the drug on 500 people, we will have a much better idea of the effect of the drug
Term
Dependent Variable
Definition

what you will measure in your experiment. It is called this because the outcome depends on what you do to the plants

Example: how tall plants grow with water or sugar water

dependent variables are always on the y-axis (vertical axis) on a graph

Term
Independent Variable
Definition

a factor that might influence the dependent variable during the experiment

Example: the sugar water that was used on the plants

independent variables are always on the x-axis (horizontal axis) on a graph

Term

Diagram of Microscope

(Parts Labeled)

Definition
[image]
Term
Some Basic Stains and Indicators
Definition

Iodine

Methylene Blue

Bromthyol Blue

Term
Enzymes
Definition

a type of protein that speeds up the rate of a chemical reaction without changing the reaction, and without being used up during the reaction. Every chemical reaction in living organisms (digestion, respiration, etc.) requires enzymes to help the reactions go forward at the exact time when they are needed. In this way, enzymes help regulate homeostasis. Enzymes are also proteins so they are affected by their environment. Each enzyme works best at a specific temperature and pH - depending on where the enzyme is found

Example: enzymes in the stomach work best at a slightly acidic pH

If the conditions are not correct, the enzymes will denature, or unfold, and will not work

Term
Asexual Reproduction
Definition
all genetic material from one original parent is passed on to the offspring, the clones. The offspring are usually genetically identical to the parent (unless a mutation occurs). This allows for no variability within a population, and therefore populations of these organisms can have a difficult time evolving if their environment changes suddenly
Term
Sexual Reproduction
Definition
two parents pass on genetic material to their offspring. This provides genetic variability in a population. Males make sperm and females make eggs, each sex cell contains 1/2 the normal number of chromosomes for the species. When the egg and sperm combine, the normal number of chromosomes is restored. Advantages to this method include the ability to evolve in a changing environment
Term
Ecology
Definition
the scientific study of living organisms and how they interact with their environment. This includes the living factors (biotic) and the nonliving factors (abiotic) like wind, temperature, etc.
Term
Population
Definition

all individuals of one species living together in a specific area

Example: all the gray squirrels living together in Central Park

Term
Community
Definition

all the population of different species living together in a specific area

Example: all of the plants and animals living together in Central Park

Term
Ecosystem
Definition

the community and its physical environment. This includes both biotic and abiotic factors.

Example: all of the plants and animals living together in Central Park, as well as the temperature, the amount of water available, the amount of sunlight, etc.

Term
Niche
Definition
an organism's "role" in the ecosystem. In other words, what the organism does, where it lives, when it is active, what it eats, etc.
Term
Autotroph
Definition

"self feeder", an organism that is capable of producing its own food

Example: plants

Term
Heterotroph
Definition

"other feeder", an organism that must eat other organisms to survive.

Example: all animals

Term
Herbivore
Definition

an organism that eats plants

Example: deer, rabbits, cows

Term
Carnivore
Definition

an organism that eats other animals

Example: rattlesnakes, lions, hawks

Term
Omnivore
Definition

an organism that eats both plants and animals

Example: humans, raccoons, skunks

Term
Decomposer
Definition

organisms that recycle dead and decaying matter into the environment

Example: bacteria

Term
Carrying Capacity
Definition
the maximum number of organisms that an ecosystem can support. This has to do with space, available resources like food and water, number of mates, etc. If a population exceeds its carrying capacity there is usually a rapid dramatic drop in survival of the population
Term
Competitive Exclusion Principle
Definition
no two species can occupy exactly the same niche in an ecosystem. One will always out-compete the other. The weaker species will either move to a new habitat, or change their behavior slightly so that the niches are not exactly the same
Term
Food Chain
Definition

all organisms in a population are linked by a complex of web interactions. The removal of one species has dramatic effects on all of the other species in the ecosystem (although it might not be obvious to us).

Food webs and chains show the feeding relationships of organisms in an ecosystem. Arrows point from the species that is being eaten to the species that is doing the eating

Term
Food Web
Definition
same as a food chain, only more complex
Term
Energy Pyramids
Definition
The sun provides the energy for life on earth. Herbivores eat the plants, carnivores eat the herbivores, and omnivores eat the plants, the herbivores, and sometimes the carnivores. Therefore, all life is connected to the sun and to the plants on earth. The energy pyramid shows the relationships among the different groups of organisms. The producers are on the bottom of the pyramid because they support all of the upper levels. Therefore, there are many more autotrophs in the world (by mass) than any other type of organism. This means most of the energy is stored in the producers. As organisms in the upper levels of the pyramid eat organisms in the lower levels, some energy is lost. Approximately 10% of energy is lost at each step as you go up the pyramid. Because of this, there have to be many more individuals supporting the lower levels than the upper levels. In the end, the decomposers recycle all the nutrients so plants can begin the food chain again
Term
Ecological Succession
Definition
the process by which an existing community is slowly replaced by another type of communiy
Term
Climax Community
Definition
a mature, stable community that is the last stage of ecological succession. Natural communities change over long periods of time. These gradual changes form new communities. The new communities will continue to change until a climax community is reached. Once a climax community has formed, the ecosystem is stable over time unless there is a natural disruption like a fire or flood, or human impact like clear-cutting a forest. If these occur, then succession will begin all over again
Term
Centrioles
Definition
used for cell divison, and only in animal cells
Term
Cytoskeleton
Definition
supports and moves stuff around inside the cell. This is made of microtubules and is also known as a "conveyor belt".
Term
Primary Succession
Definition

the formation of a community in a place that did not previously support life. This is a very slow process because soil has to form. Once soil has formed, moss and lichen grow, then grasses.

Example: a bare rock face, or lava fields after a volcanic eruption

Term
Secondary Succession
Definition
succession that begins after there has been a disturbance in a climax community. This is much faster than primary succession because soil is already formed.
Term
Succession in Lakes (Pond Succession)
Definition
Succession also occurs in lakes. Leaves and other debris fall on the lake, organisms die, and the floor of the lake start to accumulate new layers. As the lake's bottom fill in, it becomes shallow. More plants grow, and the lake fills in even more, becoming a swamp. This may continue until the lake has totally filled in and becomes a forest.
Term
Human Population Growth
Definition

population rates are growing at an alarming rate:

1930's - world's population is around 2 billion

1970's - world's population is around 4 billion

1995 - world's population is around 5.7 billion

2002 - world's population is around 6.1 billion

The more people on earth, the more pollution, destruction of habitat, etc.

Term
Limiting Factors
Definition

factors that halt any further growth in a population.

Example: food availability, clean water, space, pollution, etc.

Term
Carrying Capacity
Definition
the size of a population that can be supported by the environment. Earth has a carrying capacity for humans, we just don't know what it is.
Term
Biomagnification
Definition
when a pollutant gets in the food chain, it becomes concentrated in the top-level consumers
Term
Pollution
Definition
adding anything to the environment that makes it less fit for living things
Term
Noise Pollution
Definition
loud noises can cause hearing loss and disrupt normal behaviors in animals.
Term
Water Pollution
Definition
much of the available fresh water on Earth is polluted.
Term
Organic Wastes
Definition
use up O2 in the water, too many organic wastes depletes O2 levels and kills fish. This leads to eutrophication (see card #71 for definiton). Wastes stimulate algae growth which kills off other plants. The lake fills in with plant remains and its depth is reduced
Term
Inorganic Wastes
Definition

mining and industry release pollutants like mercury, lead, and pesticides which are poisonous. This leads to biological magnification, which is the accumulation of chemicals in organisms at each higher level on the food chain. The end of the chain has the highest concentration of toxin  (see card #65 as well)

Example: DDT (pesticide) sprayed on crops, bugs get dprayed or eat the plants, fish eat the bugs, bald eagles eat the fish. Bald eagles accumulate huge amounts of DDT in their bodies due to the large amounts of fish they eat. This led to the bald eagle almost going extinct.

Term
Eutrophication
Definition
accelerated aging in lakes or ponds
Term
Disease-causing Microorganisms
Definition

these enter the water from untreated sewage and wastes, which can make humans very sick if we drink untreated water.

Example: E. Coli as well as other infectious bacteria and viruses can enter streams from areas where livestock wander

Term
Thermal Pollution
Definition
changes in water temperature from cooling industrial equipment kill the organisms living in the lake/stream.
Term
Oil Spills
Definition
oil is toxic to all life forms including humans
Term
Radioactive Wastes
Definition
this includes waste from nuclear reactors and from some forms of mining. Exposure to very small amounts is harmful to all living organisms
Term
Air Pollution
Definition
200 million tons of pollutants are released into the atmosphere each year
Term
Sulfur Dioxide
Definition
produced by burning coal and oil, combines in the atmosphere to form acid which comes back to earth in the form of acid rain
Term
Land Pollution
Definition
tons of solid waste and refuse are produced by humans each day. It is then put in landfills or is burned. We have limited space for landfills and burning causes its own pollution.
Term
Controlling Pollution
Definition
New techniques of sanitation, newly made laws to control air and water pollution, and proper disposal of hazardous materials are helping reduce pollution
Term
Conserving Natural Resources
Definition
Reforestation, conservation, recycling of materials and finding alternative sources of power are all helping to conserve our natural resources
Term
Renewable Resources
Definition

air, water, soil, sunlight, and living things

can be renewed if managed well

Term
Nonrenewable Resources
Definition

coal, oil, natural gas, metals, and minerals

can only be removed once

Term
Conserving Soil
Definition
Although soil is renewable, the process is very slow. It is important to prevent loss of topsoil through erosion and nutrient depletion. Farmers are using inventive techniques like terracing, contour farming, windbreaks, and crop rotation to preserve their soil.
Term
Conserving Forests
Definition
Forest products are widely used (making wood, paper, fabrics, etc.) Poor tree-cutting practices can cause permanent damage to the ecosystem. New conservation practices include sustained-yield tree farming and reforestation.
Term
Conserving Wildlife
Definition
The growth of cities and the and the paving of land has led to the destruction of natural habitats. Hunting has brought many animals to the edge of extinction and pesticides have had harmful effects on many wild animals. Concern for animals has resulted in many wildlife conservation practices: hunting and fishing laws, wild animal preserves, fish hatcheries, restricting pesticide and herbicide use, and legal protection for endangered species. All of which are helping to conserve wildlife.
Term
Controlling Pests Biologically
Definition

Scientists have started making pesticides that break down quickly, but they have to be applied often and are expensive. A number of alternatives to chemicals have also been developed.

-Use of natural enemies. Example: ladybugs are released to control aphids (pests)

-Pheromones (see card #87 )  are used to lure pests into traps

-Sterile males can be released into the population to mate with females so that no young are produced.

Term
Pheromones
Definition
Natural sex attractants
Term
O-Zone Layer
Definition
The O-Zone Layer protects us from the sun's harmful rays. CFC's damage it.
Term
Parasitism
Definition

A type of relationship where one organism benefits and the other is harmed.

Example: Tapeworm

Term
Mutualism
Definition

A type of relationship where both organisms benefit.

Example: Bee and Flower

Term
Commensalism
Definition

A type of relationship where one organism benefits and the other is neutral

Example: Barnacles on a Whale

Term
Endocytosis
Definition
A type of transport where a big particle is engulfed by a cell.
Term
Exocytosis
Definition
A type of transport where a big particle is removed.
Term
Phagocytosis
Definition
"Cellular Eating", the taking in of food into a cell.
Term
Pinocytosis
Definition
"Cellular Drinking", the taking in of liquid into a cell.
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